ccan/io stores the context pointer for io_new_conn, but we were using
`daemon->listeners` which we reallocate, so it can use a stale pointer.
```
0x3e1700 call_error
ccan/ccan/tal/tal.c:93
0x3e1700 check_bounds
ccan/ccan/tal/tal.c:165
0x3e1700 to_tal_hdr
ccan/ccan/tal/tal.c:174
0x3e1211 to_tal_hdr_or_null
ccan/ccan/tal/tal.c:186
0x3e1211 tal_alloc_
ccan/ccan/tal/tal.c:426
0x3db8f4 io_new_conn_
ccan/ccan/io/io.c:91
0x3dd2e1 accept_conn
ccan/ccan/io/poll.c:277
0x3dd2e1 io_loop
ccan/ccan/io/poll.c:444
0x3419fa main
connectd/connectd.c:2081
```
Fixes: #6060
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>